The field of regenerative medicine encompasses therapies designed to aid the repair, replacement, or regeneration of damaged cells, tissues, or organs. One branch of regenerative medicine includes cell therapies that rely on embryonic stem cells (ES), which have the potential to give rise to a diverse range of cell types. ES-based cell therapies have the promise of treating a variety of health conditions including Alzheimer's Disease, Parkinson's Disease, stroke, spinal injuries, heart attack, renal failure, osteoporosis, type I diabetes, multiple sclerosis, rheumatoid arthritis, burns, and wounds. However, the progress of such therapies has been hindered by a range of factors including the possibility of immune rejection of ES cells derived from a donor who is immunologically incompatible with the recipient.